OBJECTIVE: To validate the efficacy of PAPNET for cervical cytology screening. STUDY DESIGN: From a total of 50,000 gynecologic cases we selected 24 primarily negative smears from patients who, during follow-up, developed a precancerous lesion or cancer in a short time, ranging from a few months to two years. These negative smears were rescreened by the PAPNET automated system and reevaluated by two observers. A third observer blindly reevaluated the same cases manually. RESULTS: Reevaluation after PAPNET screening showed one false negative smear, for a rate comparable to that of manual reevaluation, which also reclassified the same case. The time required to interpret a smear using the PAPNET system was approximately one minute, while the time required for conventional manual screening was approximately five. CONCLUSION: PAPNET is an efficient and fast screener for the detection of precancerous cervical lesions and cancer.